An Algorithm for Optimal Sizing of the Capacitor Banks Under Nonsinusoidal and Unbalanced Conditions

In non-sinusoidal and unbalanced systems, optimal sizing of the capacitor banks is not a straightforward task as in sinusoidal and balanced systems. In this paper, by means of qualitative and quantitative analysis, it is interpreted that the classical capacitor selection algorithm widely implemented in Reactive Power Control (RPC) relays does not achieve optimal power factor improvement in non-sinusoidal and unbalanced systems. Accordingly, a computationally efficient algorithm is proposed to find the optimal capacitor bank for smart RPC relays. It is further shown in a simulated unbalanced and non-sinusoidal test case by using Matlab software that the proposed algorithm provides better power factor improvement when compared with the classical algorithm. It is also figured out from the simulation results that both algorithms cause almost the same harmonic distortion and unbalance deterioration levels in the system.